The most important part of learning an art like tai chi is the foundation. If the foundation is good, the artist can excel. However, if the foundation is neglected, the artist will never achieve greatness.
In fact, it is can be said that mastery can be achieved by those who only practice basics, but it can never be achieved by those who only practise the advanced methods.
Whether you are completely new to tai chi, or you are a student with decades of experience, I strongly suggest that you spend plenty of time working on the basic exercises taught in level one, before you go on to the more advanced and “sophisticated” practices of the advance levels.